#define _CRT_SECURE_NO_WARNINGS 1

class Solution {
public:
    int singleNumber(vector<int>& nums)
    {

        int ret = 0;
        int a = 0;

        for (int i = 0; i < 32; i++)
        {
            int sum = 0;
            for (auto a : nums)
                if ((a >> i) & 1 == 1)sum++;
            sum %= 3;
            if (sum == 1)ret |= 1 << i;

        }
        return ret;
    }
};
